docs: def com_google_fonts_check_linegaps(ttFont):
    """Checking Vertical Metric Linegaps."""
    if ttFont["hhea"].lineGap != 0:
      yield WARN, Message("hhea", "hhea lineGap is not equal to 0.")
    elif ttFont["OS/2"].sTypoLineGap != 0:
      yield WARN, Message("OS/2", "OS/2 sTypoLineGap is not equal to 0.")
    else:
      yield PASS, "OS/2 sTypoLineGap and hhea lineGap are both 0."